mail issues questions

[Geoff Shang]

On Mon, 28 Feb 2011, Uri Even-Chen wrote:

> Yahoo and Hotmail are very important. Why did you set up SPF and DKIM?

SPF and DKIM are technologies which should make it more likely that your 
mail will be accepted, not less.

SPF seeks to define which servers are authorised to send Email for a 
particular domain, and DKIM uses public key technology to try to prove the 
authenticity of an Email.  Neither scheme is mandatory at this stage, 
which of course limits their effectiveness, but in my experience they do 
tend to help with getting your Email through.

I know that Yahoo won't even let you sign up to their feedback loop if you 
don't use either DKIM or SPF, or at least that used to be the case.

We were having issues sending to Yahoo before we implemented DKIM.  We 
used to host a 750+ member mailing list with lots of Yahoo addresses, and 
we used to get a lot of soft rejects and massive mail queues.  Since we 
implemented DKIM, the issues reduced considerably.

Having said that, I'm on the Mailman users mailing list and people there 
regularly complain about difficulties delivering to Yahoo, AOL and 
Hotmail.

It's gotten to the point now where people sending out Email have to jump 
through whatever hoops receiving mailservers want you to jump through if 
you want to be able to send them mail.

Let me give you an example of the kind of thing that can go on:

I used to work as a sysadmin for a non-profit advocacy organisation in the 
USA.  They ran two dedicated servers which hosted several domains (some 
theirs and some they hosted as a courtesy to other groups).  Most of these 
domains had several mailing lists hosted on them.

While I was sysadmin, I also volunteered on their Internet radio project. 
I noticed that one person would periodically stop receiving our Email and 
would need to contact their ISP to get us unblocked.  Some time would go 
by and then the cycle would repeat.

It turned out that another Roadrunner customer who had subscribed 
willingly to one of our mailing lists had decided that they didn't want to 
receive it anymore, and rather than unsubscribe normally, they were 
marking messages which came from this list as spam.  Roadrunner's systems 
then automatically flagged all mail from our server as spam, meaning that 
no Roadrunner customer could receive any Email from our server at all.

I managed to get subscribed to their feedback loop and also managed to 
figure out which Email address was doing the blocking and removed them 
manually from our list.  All this was no thanks to Roadrunner who would 
not tell me the address in question so I could remove it.

For anyone sending out any amount of Email, the onus seems to be on you to 
sign up to all the feedback loops you can in order to keep your mail 
flowing.  Yes this shouldn't be necessary but it seems like this is what 
everyone wants.

And by all means use SPF and DKIM, they seem like the way forward.  Just 
be sure it's configured right.  I know someone who has a missconfigured 
SPF setup and our server will not accept mail from them.

Alot of good info, including pointers to feedback loops for major Email 
providers is here: 
http://www.spamhaus.org/faq/answers.lasso?section=ISP%20Spam%20Issues

I know all of this doesn't help much with the original question, as the 
servers in question seem to accept the mail, at least initially.

HTH,
Geoff.